This invention relates to video distribution systems and particularly to such systems operating at frequencies of around 29 GHz or 40 GHz. The invention also relates to adaptable microwave transmitters.
United States Patent Specification U.S. Pat. No. 4,747,160 describes such a video distribution system (in the form of a low power, multi-function cellular television system) comprising a plurality of microwave transmitters each having a transmitting antenna at a node of a respective cell for transmitting a microwave signal in that cell, and subscribing receivers in each cell for receiving the microwave signal transmitted in that cell.
Each cellular transmitting antenna may be composed of individual antenna sectors (see for example the four individual sector antennas 62 of each transmitter station 60 of FIGS. 4A and 5B of U.S. Pat. No. 4,747,160) for transmitting the microwave signal towards different sectors of the cell. The system of U.S. Pat. No. 4,747,160 is a multiple-cell arrangement based on using substantially omni-directional transmitting antennas. Thus, all the individual antenna sectors of a given antenna are fed with the same microwave signal for them to transmit throughout that cell, i.e. the microwave signal has the same power level, frequency, phase and polarization for all the sectors of that omni-directional transmitting antenna.